Bert is a muppet
from Sesame Street
who lives with Ernie
in a basement apartment of 1-2-3 Sesame.
Bert was originally envisioned as Ernie's father, but because Ernie was always tricking Bert, the Powers That Be decided that may be too 'controversial' and simply made them buddies, though Bert is still the more mature one.
There has been much speculation about Bert and Ernie's sexuality, but the official word has always been that they're buddies/like brothers.
Bert loves pigeons, of which he has several (most notable, Bernice). He also collects bottle caps and paper clips, has a nephew named Brad and a brother named Bart. He had a girlfriend briefly.
Picture: http://members.tripod.com/~hooperfan/Bert.jpg (More at http://members.tripod.com/~hooperfan/index-2.html)